1. Field of the Invention
The present invention relates to slot bar code readers generally and, more particularly, to a novel slot bar code reader that incorporates means to immediately identify tampering when the bar code reader is in use and which provides an integral test system for automatically testing the operation of the bar code reader when the bar code reader is installed in the field, the latter being useful, alos, for testing the bar code reader while on the manufacturing line.
2. Background Art
Bar codes have found application in a wide variety of applications as an information source, typically for digital processors. Such bar codes are used at point-of-sale in merchandising for pricing and inventory count, in controlled personnel access systems, for time-and-attendance reporting, and in manufacturing for work-in-prcess and inventory control, to name only a few applicatons. The bar codes themselves comprise a series of parallel lines, typically in the range of about 1/8" to 1" in height and from about 1 to mill to about 50 mills in thickness, arrayed on a contrasting background. The lines may variously have unequal spacing and/or thickness determined by the informaiton "stored" in the bar code. A bar code is "read" by serially illuminating the bars, with the bars absorbing light and the background reflecting light. The resulting pattern of reflection and nonreflection is sensed by a light detecting device which provides input to the digital processor. The bar code reader may be of the type that is passed over the bar code or of the type with which the bar code is moved passed the bar code reader, the latter reader usually having a slot through which a card bearing the bar code is passed.
A problem with the latter type of bar code reader is that it is subject to tampering. This is particularly a problem in time-and-attendance reporting situations where employees are required to, for example, pass their employee identification cards containing an identifying bar code through a slot bar code reader when entering and exiting their place of work. The information thus obtained may be used for payroll and other purposes. Some employees have found that, by disabling the reader, tardiness or early quitting cannot be detected. One method by which a slot bar code reader may be disabled is to place a piece of tape or similar object over the window in the reader through which the bar codes are read. This tampering may not be discovered for some time, during which period of time no time-and-attendance data is being collected, and, of course, the guilty employee cannot be readily identified.
It would be desirable, then, to be able to immediately identify a tampering condition so that the condition can be promptly corrected and so that the employee responsible can be identified.
According, it is a principal object of the present invention to provide a method and means for the immediate indication that a slot bar code reader has been disabled.
It is a further object of the invention to provide such method and means that may also be employed to test the slot bar code reader while it is in use and to use such method and means to test the reader on the factory assembly line.
It is another object of the invention to provide such method and means that is easily and economically incorporated into the reader.
Other objects of the present invention, as well as particular features and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawings figures. SUMMARY OF THE INVENTION
The present invention accomplishes the above objects, among others, by providing, in a preferred embodiment, a method and means for identifying a tampering or malfunction condition in a slot bar code reader which include providing a test signal to the detector in the reader which test signal is present whenever a bar code is not being read. If, for whatever reason, the test signal is not being detected, an alarm or other signal means identifies that a tampering condition is present or that there is some malfunction with the reader. If the lack of a signal is due to tampering, the person responsible can be immediately identified. In any case, the condition can be promptly corrected. The test mode may also be used during the manufacturing process to test the bar code reader. The test signal is provided to the detector in the reader by disposing a reflective surface at the place in the slot that a bar code would be read, so that the test signal from the light source may be reflected to the detector.